A DSP based hard disk drive servo test stand

The paper reports the development of a hard disk drive (HDD) servo test stand developed to demonstrate the principles of a hard disk drive servo system for teaching and research. The test stand consists of a servo written head disk assembly, electronic circuits to process the HDD signal to obtain position information, a 16-bit digital signal processor (DSP) and a spindle motor controller. Hard disk drive servo control related internal signals such as the read signal, peak detector output, servo gate and servo bursts are made available for probing. A host PC is used for down loading commands and controller parameters to the DSP and up-loading the results of the servo system for display and post-processing. Implementation results of a PTOS servo controller and system identification are presented.